Relating white matter microstructure in theoretically defined addiction networks to relapse in alcohol use disorder.

Theoretical models group maladaptive behaviors in addiction into neurocognitive domains such as incentive salience (IS), negative emotionality (NE), and executive functioning (EF). Alterations in these domains lead to relapse in alcohol use disorder (AUD). We examine whether microstructural measures in the white matter pathways supporting these domains are associated with relapse in AUD. Diffusion kurtosis imaging data were collected from 53 individuals with AUD during early abstinence. We used probabilistic tractography to delineate the fornix (IS), uncinate fasciculus (NE), and anterior thalamic radiation (EF) in each participant and extracted mean fractional anisotropy (FA) and kurtosis fractional anisotropy (KFA) within each tract. Binary (abstained vs. relapsed) and continuous (number of days abstinent) relapse measures were collected over a 4-month period. Across tracts, anisotropy measures were typically (i) lower in those that relapsed during the follow-up period and (ii) positively associated with the duration of sustained abstinence during the follow-up period. However, only KFA in the right fornix reached significance in our sample. The association between microstructural measures in these fiber tracts and treatment outcome in a small sample highlights the potential utility of the three-factor model of addiction and the role of white matter alterations in AUD.

Familial Associations of Prevalence and Cause-Specific Mortality for Thoracic Aortic Disease and Bicuspid Aortic Valve in a Large-Population Database.

BACKGROUND: Thoracic aortic disease and bicuspid aortic valve (BAV) likely have a heritable component, but large population-based studies are lacking. This study characterizes familial associations of thoracic aortic disease and BAV, as well as cardiovascular and aortic-specific mortality, among relatives of these individuals in a large-population database. METHODS: In this observational case-control study of the Utah Population Database, we identified probands with a diagnosis of BAV, thoracic aortic aneurysm, or thoracic aortic dissection. Age- and sex-matched controls (10:1 ratio) were identified for each proband. First-degree relatives, second-degree relatives, and first cousins of probands and controls were identified through linked genealogical information. Cox proportional hazard models were used to quantify the familial associations for each diagnosis. We used a competing-risk model to determine the risk of cardiovascular-specific and aortic-specific mortality for relatives of probands. RESULTS: The study population included 3 812 588 unique individuals. Familial hazard risk of a concordant diagnosis was elevated in the following populations compared with controls: first-degree relatives of patients with BAV (hazard ratio [HR], 6.88 [95% CI, 5.62-8.43]); first-degree relatives of patients with thoracic aortic aneurysm (HR, 5.09 [95% CI, 3.80-6.82]); and first-degree relatives of patients with thoracic aortic dissection (HR, 4.15 [95% CI, 3.25-5.31]). In addition, the risk of aortic dissection was higher in first-degree relatives of patients with BAV (HR, 3.63 [95% CI, 2.68-4.91]) and in first-degree relatives of patients with thoracic aneurysm (HR, 3.89 [95% CI, 2.93-5.18]) compared with controls. Dissection risk was highest in first-degree relatives of patients who carried a diagnosis of both BAV and aneurysm (HR, 6.13 [95% CI, 2.82-13.33]). First-degree relatives of patients with BAV, thoracic aneurysm, or aortic dissection had a higher risk of aortic-specific mortality (HR, 2.83 [95% CI, 2.44-3.29]) compared with controls. CONCLUSIONS: Our results indicate that BAV and thoracic aortic disease carry a significant familial association for concordant disease and aortic dissection. The pattern of familiality is consistent with a genetic cause of disease. Furthermore, we observed higher risk of aortic-specific mortality in relatives of individuals with these diagnoses. This study provides supportive evidence for screening in relatives of patients with BAV, thoracic aneurysm, or dissection.

High-intensity statin therapy reduces risk of amputation and reintervention among patients undergoing lower extremity bypass for chronic limb-threatening ischemia.

OBJECTIVE: Statins are considered standard-of-care medical therapy for patients undergoing lower extremity bypass (LEB) procedures for chronic limb-threatening ischemia (CLTI). It is unclear, however, whether up-titrating and maintaining patients on higher-intensity statin medications following LEB improves limb salvage outcomes. This study was designed to evaluate whether high-intensity statin therapy impacts the risk of amputation and reintervention following LEB for patients with CLTI. METHODS: The IBM MarketScan database was used to identify adult patients (18-99 years old) who underwent a LEB for CLTI between 2008 and 2017. Patients lacking insurance covering drug reimbursement or those who already had undergone amputation before time of bypass were excluded. Using pharmacy claims and national drug codes to define statin intensity, patients were stratified into three groups: high-intensity, low-intensity, and limited statin therapy. The association between intensity of statin therapy and need for reintervention and/or major amputation after LEB was analyzed using Kaplan-Meier curves and risk-adjusted Cox proportional hazard models. RESULTS: A total of 25,907 patients who underwent LEB for CLTI were identified, of which 6696 (26%) were maintained on high-dose statins, 9297 (36%) were on low-dose statins, and 9914 (38%) had inconsistent pharmacy claims for statin therapy after surgery. Patients on high-intensity statins were, on average, younger and more likely to be male with comorbid disease (diabetes, hypertension, hyperlipidemia, obesity, renal insufficiency, ischemic heart disease, cerebrovascular disease, and tobacco abuse) than patients on low-intensity statins or limited statin therapy (P < .001 for all comparisons). Following LEB, 6649 patients (25.6%) required a reintervention, and 2550 patients (9.8%) went on to have a major amputation during follow-up. Patients maintained on high-intensity statins after LEB had a significantly lower likelihood of requiring a reintervention (hazard ratio [HR], 0.48; 95% confidence interval [CI], 0.45-0.51; P < .001) or amputation (HR, 0.27; 95% CI, 0.24-0.30; P < .001) as compared with patients on limited statin therapy. Further, there was a dose-dependent effect for these outcomes relative to patients on low-intensity statins in risk-adjusted models, and it was independent of whether an autologous vein graft was used for the LEB. Finally, among patients who underwent a reintervention, high-dose statin therapy also significantly reduced the HR for subsequent amputation (HR, 0.21; 95% CI, 0.18-0.25; P < .001). CONCLUSIONS: Patients with CLTI on high-intensity therapy following LEB had a significantly lower risk of requiring subsequent reintervention and amputation when compared with patients on low-intensity statins or with limited statin use. These data suggest that patients with CLTI should be up-titrated and/or maintained on high-intensity statins following revascularization whenever possible.

Predictors of Adherence to Anti-Impulse Therapy among Patients Treated for Acute Type-B Aortic Dissections.

BACKGROUND: Medical management remains the mainstay of treatment for patients who present with acute Type-B aortic dissections (TBAD). However, it is unclear whether patients maintain adherence to their anti-impulse therapy medication regimen following hospital discharge. This study was designed to evaluate rates and predictors of medication adherence among insured patients treated for acute TBAD. METHODS: We used the Truven MarketScan database to identify US patients who presented with an acute TBAD between 2008 to 2017. Patients with continuous health insurance (Commercial or Medicare Part C) for at least 12 months after TBAD diagnosis were stratified by whether they underwent open surgical repair (OPEN), thoracic endovascular aortic repair (TEVAR), or only medication management (MED). Prescriptions for anti-impulse therapy medications were captured and adherence was defined by the medication possession ratio as > 80% fill rate over the follow-up period. Mixed-effects logistic regression models were used to identify predictors for medication adherence. RESULTS: A total of 6,702 patients were identified that underwent treatment for TBAD (3% TEVAR, 9% OPEN, & 74% MED), whereas 14% received no intervention. The overall mean (±SD) rate of adherence to anti-impulse therapy was 72.6% ( ± 26), and varied based on type of TBAD intervention (73.4% TEVAR, 74.4% OPEN, & 72.4% MED). The majority of patients across all treatment groups were prescribed ≥ 2 agents, with beta-blockers and diuretics being the most common medication classes. The odds of adherence to anti-impulse therapy were significantly lower for patients who were female (OR: 0.93; 95%CI:0.85-0.99; P = 0.03), aged < 45 years (OR: 0.81; 95%CI:0.69-0.96; P < 0.001), nonadherent on preexisting therapy (OR: 0.81; 95%CI: 0.73-0.89; P < 0.001), and when medications were obtained in less than a 90 days supply from retail pharmacies. CONCLUSIONS: Nearly a quarter of patients were nonadherent with anti-impulse therapy prescribed following an acute TBAD, which was more likely among younger female patients not adherent before their event. Adherence was improved among patients who received their medications by mail and when a > 90 days supply was prescribed. These findings may be used by quality improvement initiatives to improve medication adherence following TBAD and help prevent further complications.

Core Fermentation (CoFe) granules focus coordinated glycolytic mRNA localization and translation to fuel glucose fermentation.

Glycolysis is a fundamental metabolic pathway for glucose catabolism across biology, and glycolytic enzymes are among the most abundant proteins in cells. Their expression at such levels provides a particular challenge. Here we demonstrate that the glycolytic mRNAs are localized to granules in yeast and human cells. Detailed live cell and smFISH studies in yeast show that the mRNAs are actively translated in granules, and this translation appears critical for the localization. Furthermore, this arrangement is likely to facilitate the higher level organization and control of the glycolytic pathway. Indeed, the degree of fermentation required by cells is intrinsically connected to the extent of mRNA localization to granules. On this basis, we term these granules, core fermentation (CoFe) granules; they appear to represent translation factories, allowing high-level coordinated enzyme synthesis for a critical metabolic pathway.

Long-Term Impact of Vascular Surgery Stress on Frail Older Patients.

BACKGROUND: Frailty is a syndrome where the ability to cope with acute physiological stress is compromised, although it is unclear what impact this stress has on long-term outcomes. Vascular-Physiological and Operative Severity Score for enumeration of Mortality and Morbidity is a validated method for calculating levels of stress associated with vascular procedures. We designed this study to evaluate the long-term impact of different levels of surgical stress among frail older patients undergoing vascular surgery procedures. METHODS: We identified all independently living patients who underwent prospective frailty assessment followed by an elective vascular surgery procedure captured in the Vascular Quality Initiative registry (endovascular abdominal aortic aneurysm [AAA] repair, thoracic endovascular aortic repair, suprainguinal and infrainguinal bypass, peripheral vascular intervention, carotid endarterectomy, and open AAA) at an academic institution between January 2016 and July 2018. Patient- and procedure-level data were obtained from our institutional data warehouse and Vascular Quality Initiative database, and used to calculate Vascular-Physiological and Operative Severity Score for enumeration of Mortality and Morbidity scores. The association between frailty and composite outcome of any major complications (surgical site infection; graft thrombectomy; major amputation; adverse cardiac, pulmonary, or neurologic event; acute renal insufficiency; and/or reoperation related to the index procedure), nonhome living status, or death within 1 year after low-, medium-, and high-stress vascular procedures was evaluated using bivariate and logistic regression models. RESULTS: A total of 163 patients were identified (70% male, mean age 67.8 years) who underwent open AAA repair (6%), endovascular AAA repair (21%), thoracic endovascular aortic repair (7%), suprainguinal bypass (5%), infrainguinal bypass (18%), carotid endarterectomy (18%), or peripheral vascular interventions (25%), which included 44 (27%) patients diagnosed with frailty before surgery. Overall, frail patients had significantly higher rates of the 1-year composite outcome (48% frail versus 27% nonfrail; P = 0.012) when compared with nonfrail patients, with a significant dose-dependent effect as the level of stress increased. In comparison, increasing levels of surgical stress had a negligible effect on long-term outcomes among nonfrail patients. The interaction between frailty and high surgical stress was found in adjusted regression models to be a significant predictor of adverse outcomes within 1 year after vascular surgery (odds ratio, 3.3; 95% confidence interval, 1.3-8.6; P < 0.01). CONCLUSIONS: Frail patients who undergo high-stress vascular procedures have a significantly higher rate of complications leading to loss of functional independence and mortality within the year after their surgery. These data suggest that estimates of surgical stress should be incorporated into clinical decision making for frail older patients before and after surgery.

Vascular surgery triage during the coronavirus disease 2019 pandemic.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic has resulted in a marked increase in hospital usage, medical resource scarcity, and rationing of surgical procedures. This has created the need for strategies to triage surgical patients. We have described our experience using the American College of Surgeons (ACS) COVID-19 guidelines for triage of vascular surgery patients in an academic surgery practice. METHODS: We used the ACS guidelines as a framework to direct the triage of vascular surgery patients during the COVID-19 pandemic. We retrospectively analyzed the results of this triage during the first month of surgical restriction at our hospital. Patients undergoing surgery were identified by reviewing the operating room schedule. We reviewed the electronic medical records (EMRs) and assigned an ACS category, condition, and tier class to each completed surgery. Surgeries that were postponed during the same period were identified from a prospectively maintained list. We reviewed the EMRs for all postponed surgeries and assigned an ACS category, condition, and tier class to each surgery. We reviewed the EMRs for all postponed procedures to identify any adverse events related to the treatment delay. RESULTS: We performed 69 surgeries in 52 patients during the study period. All surgeries were performed to treat emergent, urgent, or time-sensitive elective diagnoses. Of the 69 surgeries, 47 (68%) were from tier 3 and 22 (32%) from tier 2b. We did not perform any surgeries from tier 1 or 2a. We postponed surgery for 66 patients during the same period, of which 36 (55%) were from tier 1, 22 (33%) from tier 2a, 5 (8%) from tier 2b, and 3 (5%) could not be assigned a tier class. No tier 3 surgeries were postponed. Of the 66 patients, 3 (4.5%) experienced an adverse event that could be attributed to the treatment delay. CONCLUSIONS: The ACS triage guidelines provided an effective method to decrease vascular surgical volumes during the COVID-19 pandemic without an increase in patient morbidity. We believe the clinical utility of the guidelines would be strengthened by incorporating the SURGCON/VASCCON (surgical activity condition/vascular activity condition) threat level alert system.

Managing central venous access during a health care crisis.

OBJECTIVE: During the COVID-19 pandemic, central venous access line teams were implemented at many hospitals throughout the world to provide access for critically ill patients. The objective of this study was to describe the structure, practice patterns, and outcomes of these vascular access teams during the COVID-19 pandemic. METHODS: We conducted a cross-sectional, self-reported study of central venous access line teams in hospitals afflicted with the COVID-19 pandemic. To participate in the study, hospitals were required to meet one of the following criteria: development of a formal plan for a central venous access line team during the pandemic; implementation of a central venous access line team during the pandemic; placement of central venous access by a designated practice group during the pandemic as part of routine clinical practice; or management of an iatrogenic complication related to central venous access in a patient with COVID-19. RESULTS: Participants from 60 hospitals in 13 countries contributed data to the study. Central venous line teams were most commonly composed of vascular surgery and general surgery attending physicians and trainees. Twenty sites had 2657 lines placed by their central venous access line team or designated practice group. During that time, there were 11 (0.4%) iatrogenic complications associated with central venous access procedures performed by the line team or group at those 20 sites. Triple lumen catheters, Cordis (Santa Clara, Calif) catheters, and nontunneled hemodialysis catheters were the most common types of central venous lines placed by the teams. Eight (14%) sites reported experience in placing central venous lines in prone, ventilated patients with COVID-19. A dedicated line cart was used by 35 (59%) of the hospitals. Less than 50% (24 [41%]) of the participating sites reported managing thrombosed central lines in COVID-19 patients. Twenty-three of the sites managed 48 iatrogenic complications in patients with COVID-19 (including complications caused by providers outside of the line team or designated practice group). CONCLUSIONS: Implementation of a dedicated central venous access line team during a pandemic or other health care crisis is a way by which physicians trained in central venous access can contribute their expertise to a stressed health care system. A line team composed of physicians with vascular skill sets provides relief to resource-constrained intensive care unit, ward, and emergency medicine teams with a low rate of iatrogenic complications relative to historical reports. We recommend that a plan for central venous access line team implementation be in place for future health care crises.

Regional measurements and spatial/temporal analysis of CDOM in 10,000+ optically variable Minnesota lakes using Landsat 8 imagery.

Information on colored dissolved organic matter (CDOM) is essential for understanding and managing lakes but is often not available, especially in lake-rich regions where concentrations are often highly variable in time and space. We developed remote sensing methods that can use both Landsat and Sentinel satellite imagery to provide census-level CDOM measurements across the state of Minnesota, USA, a lake-rich landscape with highly varied lake, watershed, and climatic conditions. We evaluated the error of satellite derived CDOM resulting from two atmospheric correction methods with in situ data, and found that both provided substantial improvements over previous methods. We applied CDOM models to 2015 and 2016 Landsat 8 OLI imagery to create 2015 and 2016 Minnesota statewide CDOM maps (reported as absorption coefficients at 440 nm, a440) and used those maps to conduct a geospatial analysis at the ecoregion level. Large differences in a440 among ecoregions were related to predominant land cover/use; lakes in ecoregions with large areas of wetland and forest had significantly higher CDOM levels than lakes in agricultural ecoregions. We compared regional lake CDOM levels between two years with strongly contrasting precipitation (close-to-normal precipitation year in 2015 and much wetter conditions with large storm events in 2016). CDOM levels of lakes in agricultural ecoregions tended to decrease between 2015 and 2016, probably because of dilution by rainfall, and 7% of lakes in these areas decreased in a440 by ≥3 m-1. In two ecoregions with high forest and wetlands cover, a440 increased by >3 m-1 in 28 and 31% of the lakes, probably due to enhanced transport of CDOM from forested wetlands. With appropriate model tuning and validation, the approach we describe could be extended to other regions, providing a method for frequent and comprehensive measurements of CDOM, a dynamic and important variable in surface waters.

Understanding the Effects of Optimal Combination of Spectral Bands on Deep Learning Model Predictions: A Case Study Based on Permafrost Tundra Landform Mapping Using High Resolution Multispectral Satellite Imagery.

Deep learning (DL) convolutional neural networks (CNNs) have been rapidly adapted in very high spatial resolution (VHSR) satellite image analysis. DLCNN-based computer visions (CV) applications primarily aim for everyday object detection from standard red, green, blue (RGB) imagery, while earth science remote sensing applications focus on geo object detection and classification from multispectral (MS) imagery. MS imagery includes RGB and narrow spectral channels from near- and/or middle-infrared regions of reflectance spectra. The central objective of this exploratory study is to understand to what degree MS band statistics govern DLCNN model predictions. We scaffold our analysis on a case study that uses Arctic tundra permafrost landform features called ice-wedge polygons (IWPs) as candidate geo objects. We choose Mask RCNN as the DLCNN architecture to detect IWPs from eight-band Worldview-02 VHSR satellite imagery. A systematic experiment was designed to understand the impact on choosing the optimal three-band combination in model prediction. We tasked five cohorts of three-band combinations coupled with statistical measures to gauge the spectral variability of input MS bands. The candidate scenes produced high model detection accuracies for the F1 score, ranging between 0.89 to 0.95, for two different band combinations (coastal blue, blue, green (1,2,3) and green, yellow, red (3,4,5)). The mapping workflow discerned the IWPs by exhibiting low random and systematic error in the order of 0.17-0.19 and 0.20-0.21, respectively, for band combinations (1,2,3). Results suggest that the prediction accuracy of the Mask-RCNN model is significantly influenced by the input MS bands. Overall, our findings accentuate the importance of considering the image statistics of input MS bands and careful selection of optimal bands for DLCNN predictions when DLCNN architectures are restricted to three spectral channels.

Assessment of the chlorine demand and disinfection byproduct formation potential of surface waters via satellite remote sensing.

The ability of satellites to assess surface water quality indicators such as colored dissolved organic matter (CDOM) suggests that remote sensing could be a useful tool for evaluating water treatability metrics in considering potential drinking water supplies. To explore this possibility, 24 surface water samples were collected throughout Minnesota, USA with wide ranging values of CDOM (a440; 0.41-27.9 m-1), dissolved organic carbon (DOC; 5.5-47.6 mg/L) and specific ultraviolet absorbance at 254 nm (SUVA254; 1.3-5.1 L/mg-M). Laboratory experiments were performed to quantify chlorine demand and the formation of two classes of halogenated disinfection byproducts (DBPs), trihalomethanes (THMs) and haloacetic acids (HAAs), using the uniform formation conditions (UFC) test. Chlorine demand and THMUFC were linearly correlated with CDOM (R2 = 0.97 and 0.91, respectively), indicating that CDOM is a useful predictor of these parameters. On the other hand, data comparing di- and tri-HAAUFC with CDOM were better fit by a logarithmic relationship (R2 = 0.73 and 0.87, respectively), while mono-HAAUFC was linearly correlated with CDOM (R2 = 0.46) but only for low-to moderately-colored waters (a440 ≤ 11 m-1). The correlations relating chlorine demand and DBPUFC values with CDOM were coupled with satellite CDOM assessments to estimate chlorine demand and DBPUFC values for all surface waters larger than 0.05 km2 in the state of Minnesota, USA. The resulting maps suggest that only 21.8% of Minnesota lakes would meet both the THM and HAA maximum contaminant levels, but only when pre-disinfection treatment removes 75% of DBP precursors. There are limitations to determining CDOM using satellites for high color surface waters (a440 > 11 m-1), however, leading to underpredicted values for CDOM, chlorine demand, and DBPUFC. Overall, the results demonstrate the potential benefits of satellite remote sensing for assessing potential drinking water sources and water treatability metrics.

Cost-effectiveness of repeated interventions on failing arteriovenous fistulas.

OBJECTIVE: Arteriovenous fistulas (AVFs) used for hemodialysis commonly undergo multiple percutaneous and open interventions to maintain functional patency, but it is unclear whether this strategy is cost-effective. The aim of this study was to evaluate the clinical effectiveness and cost-effectiveness of performing repeated interventions vs starting a new AVF. METHODS: We reviewed all patients with mature radiocephalic, brachiocephalic, and brachiobasilic AVFs at a single academic institution between 2007 and 2015 and assessed the clinical effectiveness of each open and percutaneous intervention to maintain functional patency after the fistula was created. These data were used to parameterize a Markov simulation model to determine the cost-effectiveness for performing an open or percutaneous intervention vs creating an AVF at a new anatomic location. This model compared strategies of creating a new AVF after the first to fourth reintervention within a 1-year time window, with the reference being creation of a new AVF on the fourth reintervention. Costs were measured from Medicare's perspective, and effectiveness was measured as quality-adjusted life-years (QALYs) and time in functional access. Incremental cost-effectiveness ratios (ICERs) were calculated by taking the ratio of the difference in cost and the difference in effectiveness between two strategies. RESULTS: A total of 720 AVFs that were created during the 8-year period reached maturity, and 407 (56%) underwent at least one intervention to maintain functional patency, with the median (interquartile range) time to first reintervention of 12.6 (10-17) months. For the strategies of creating a new AVF after the first versus the fourth reintervention, payer costs ranged from $3519 to $3922 for open procedures and $2134 to $3922 for percutaneous procedures. The ICERs for open interventions on failing AVFs were $357,143/QALY after the first reintervention and $95,876/QALY after the second reintervention. The ICERs for percutaneous interventions on failing AVFs ranged from $1,522,078/QALY after the first reintervention to $443,243/QALY after the third reintervention. CONCLUSIONS: Whereas the clinical effectiveness of performing percutaneous interventions on failing AVFs diminishes after each reintervention, they are nevertheless less costly than creating a new AVF. In comparison, our data show that creating a new AVF is cost-effective after the second open reintervention procedure.

Prognostic implications of diagnosing frailty and sarcopenia in vascular surgery practice.

OBJECTIVE: Frailty and sarcopenia are related but independent conditions commonly diagnosed in older patients that can be used to assess their ability to tolerate the stress of major vascular surgery. For surgical decision-making, however, it is important to know the prognostic implications associated with each of these conditions. The study was designed to assess the association of frailty and sarcopenia phenotypes with long-term survival of patients undergoing surgical and nonsurgical management of vascular disease. METHODS: We retrospectively reviewed all patients presenting to the vascular surgery clinic at an academic hospital between December 2015 and August 2017 who underwent prospective frailty assessment with the Clinical Frailty Scale and who had abdominal computed tomography (CT) scans performed within the preceding 12 months. A single axial CT image at the caudal end of the third lumbar vertebra was assessed to measure cross-sectional areas of skeletal muscle. Sarcopenia was defined by established criteria specific for male and female patients. After patients were stratified by frailty and sarcopenia diagnoses along with comorbidities, the association with all-cause mortality was analyzed by Kaplan-Meier curves and Cox regression models. RESULTS: A total of 415 patients underwent both frailty and sarcopenia assessment, of whom 112 (27%) met sarcopenia criteria alone, 48 (12%) met only frailty criteria, and 56 (13%) met criteria for both phenotypes. There were 199 (48%) controls who met neither criterion. Vascular operations were performed in 167 (40%) patients after frailty and sarcopenia assessment, whereas 248 (60%) patients were managed nonoperatively with median (interquartile range) follow-up after CT imaging of 1.5 (1.1-2.2) years. Patients diagnosed with either phenotype were older (mean, 65 years vs 59 years; P < .001) and more likely to be male (69% vs 54%; P < .001) compared with patients without sarcopenia or frailty. Long-term survival was significantly decreased for patients diagnosed with either frailty alone or frailty and sarcopenia who underwent surgical or nonsurgical management (log-rank, P < .001 for both comparisons). In multivariate regression models, however, frailty was the only independent variable (hazard ratio, 7.7; 95% confidence interval, 3.2-18.7; P < .001) that predicted mortality. CONCLUSIONS: Frailty and sarcopenia overlap to varying degrees in patients presenting to vascular surgery clinics and can be used alone or in combination to predict long-term survival of older patients. However, our data indicate that it was only the diagnosis of frailty that was an independent predictor of mortality and had the strongest prognostic significance in patients undergoing both surgical and nonoperative management.

Iron influence on dissolved color in lakes of the Upper Great Lakes States.

Colored dissolved organic matter (CDOM), a major component of the dissolved organic carbon (DOC) pool in many lakes, is an important controlling factor in lake ecosystem functioning. Absorption coefficients at 440 nm (a440, m-1), a common measure of CDOM, exhibited strong associations with dissolved iron (Fediss) and DOC in 280 lakes of the Upper Great Lakes States (UGLS: Minnesota, Wisconsin, and Michigan), as has been found in Scandinavia and elsewhere. Linear regressions between the three variables on UGLS lake data typically yielded R2 values of 0.6-0.9, suggesting that some underlying common processes influence organic matter and Fediss. Statistical and experimental evidence, however, supports only a minor role for iron contributions to a440 in UGLS lakes. Although both DOC and Fediss were significant variables in linear and log-log regressions on a440, DOC was the stronger predictor; adding Fediss to the linear a440-DOC model improved the R2 only from 0.90 to 0.93. Furthermore, experimental additions of FeIII to colored lake waters had only small effects on a440 (average increase of 0.242 m-1 per 100 µg/L of added FeIII). For 136 visibly stained waters (with a440 > 3.0 m-1), where allochthonous DOM predominates, DOM accounted for 92.3 ± 5.0% of the measured a440 values, and Fediss accounted for the remainder. In 75% of the lakes, Fediss accounted for < 10% of a440, but contributions of 15-30% were observed for 7 river-influenced lakes. Contributions of Fediss in UGLS lakes to specific UV absorbance at 254 nm (SUVA254) generally were also low. Although Fediss accounted for 5-10% of measured SUVA254 in a few samples, on average, 98.1% of the SUVA254 signal was attributable to DOM and only 1.9% to Fediss. DOC predictions from measured a440 were nearly identical to those from a440 corrected to remove Fediss contributions. Overall, variations in Fediss in most UGLS lakes have very small effects on CDOM optical properties, such as a440 and SUVA254, and negligible effects on the accuracy of DOC estimated from a440, data for which can be obtained at broad regional scales by remote sensing methods.

Color, chlorophyll a, and suspended solids effects on Secchi depth in lakes: implications for trophic state assessment.

Secchi depth (SD), a primary metric to assess trophic state, is controlled in many lakes by algal densities, measured as chlorophyll-a (chl-a) concentration. Two other optically related water quality variables also directly affect SD: non-algal suspended solids (SSNA ) and colored dissolved organic matter (CDOM, expressed as the absorption coefficient at 440 nm, a440 ). Using a database of ~1,460 samples from ~625 inland lake basins in Minnesota and two other Upper Midwest states, Wisconsin and Michigan, we analyzed relationships among these variables, with special focus on CDOM levels that influence SD values and the Minnesota SD standards used to assess eutrophication impairment of lakes. Log-transformed chl-a, total suspended solids (TSS), and SD were strongly correlated with each other; log(a440 ) had major effects on log(SD) but was only weakly correlated with log(chl-a) and log(TSS). Multiple regression models for log(SD) and 1/SD based on the three driving variables (chl-a, SSNA , and CDOM) explained ~80% of the variance in SD in the whole data set, but substantial differences in the form of the best-fit relationships were found between major ecoregions. High chl-a concentrations (> 50 µg/L) and TSS (> 20 mg/L) rarely occurred in lakes with high CDOM (a440  > ~4 m-1 ), and all lakes with a440  > 8 m-1 had SD ≤ 2.0 m despite low chl-a values (<10 µg/L) in most lakes. Further statistical analyses revealed that CDOM has significant effects on SD at a440 values > ~ 4 m-1 . Thus, SD is not an accurate trophic state metric in moderately to highly colored lakes, and Minnesota's 2-m SD criterion should not be the sole metric to assess eutrophication impairment in warm/cool-water lakes of the Northern Lakes and Forest ecoregion. More generally, trophic state assessments using SD in regions with large landscape sources of CDOM need to account for effects of CDOM on SD.

Limitations on using CDOM as a proxy for DOC in temperate lakes.

Colored dissolved organic matter (CDOM) has been widely studied as part of efforts to improve understanding of the aquatic carbon cycle, by laboratory, in situ, and remote sensing methods. We studied ecoregion-scale differences in CDOM and dissolved organic carbon (DOC) to understand variability in organic matter composition and the use of CDOM as a proxy for DOC. Data from 299 lakes across the U.S. Upper Midwest showed that CDOM, measured as absorptivity at 440 nm (a440), correlated strongly with DOC (R2 = 0.81, n = 412). Colored lakes in the Northern Lakes and Forests (NLF) ecoregion drove this relationship. Lakes in the North Central Hardwood Forests (NCHF) had low color (most had a440 < 3 m-1) and weaker CDOM-DOC relationships (R2 = 0.47). Spectral slopes and specific ultraviolet absorbance (SUVA), indicated relatively low aromaticity and non-terrestrial DOM sources in low color lakes. Multiple regression analyses that included total dissolved nitrogen (TDN) and CDOM, but not chlorophyll a, improved DOC estimates in low color lakes, suggesting a dominant contribution of non-planktonic sources of low color DOM in these lakes. Our results show that CDOM is a reliable, regional proxy for DOC in lakes where forests and wetlands dominate the landscape and the DOM is primarily terrestrial in origin. Mapping of lake DOC at broad spatial scales by satellite-derived CDOM has lower accuracy in low color lakes.

Preoperative frailty assessment predicts loss of independence after vascular surgery.

OBJECTIVE: Frailty, a clinical syndrome associated with loss of metabolic reserves, is prevalent among patients who present to vascular surgery clinics for evaluation. The Clinical Frailty Scale (CFS) is a rapid assessment method shown to be highly specific for identifying frail patients. In this study, we sought to evaluate whether the preoperative CFS score could be used to predict loss of independence after major vascular procedures. METHODS: We identified all patients living independently at home who were prospectively assessed using the CFS before undergoing an elective major vascular surgery procedure (admitted for >24 hours) at an academic medical center between December 2015 and December 2017. Patient- and procedure-level clinical data were obtained from our institutional Vascular Quality Initiative registry database. The composite outcome of discharge to a nonhome location or 30-day mortality was evaluated using bivariate and multivariate regression models. RESULTS: A total of 134 independent patients were assessed using the CFS before they underwent elective open abdominal aortic aneurysm repair (8%), endovascular aneurysm repair (26%), thoracic endovascular aortic repair (6%), suprainguinal bypass (6%), infrainguinal bypass (16%), carotid endarterectomy (19%), or peripheral vascular intervention (20%). Among 39 (29%) individuals categorized as being frail using the CFS, there was no significant difference in age or American Society of Anesthesiologists physical status compared with nonfrail patients. However, frail patients were significantly more likely to need mobility assistance after surgery (62% frail vs 22% nonfrail; P < .01) and to be discharged to a nonhome location (22% frail vs 6% nonfrail; P = .01) or to die within 30 days after surgery (8% frail vs 0% nonfrail; P < .01). Preoperative frailty was associated with a >12-fold higher risk (odds ratio, 12.1; 95% confidence interval, 2.17-66.96; P < .01) of 30-day mortality or loss of independence, independent of the vascular procedure undertaken. CONCLUSIONS: The CFS is a practical tool for assessing preoperative frailty among patients undergoing elective major vascular surgery and can be used to predict likelihood of requiring discharge to a nursing facility or death after surgery. The identification of frail patients before major surgery can help manage postoperative expectations and optimize transitions of care.

Clinical effectiveness of open thrombectomy for thrombosed autogenous arteriovenous fistulas and grafts.

OBJECTIVE: Arteriovenous (AV) fistulas are the preferred hemodialysis access for patients with end-stage renal disease, although multiple interventions are typically needed to maintain patency. When AV fistulas thrombose, however, there is debate as to whether open thrombectomy should be attempted, particularly for salvage of upper arm fistulas. This study was designed to evaluate outcomes after open thrombectomy of upper arm and forearm AV fistulas compared with AV grafts. METHODS: We identified all patients who underwent an open thrombectomy procedure for a thrombosed AV fistula or graft at a single academic medical center between January 2006 and March 2017. The specific type of AV fistula or graft was evaluated, as were the patients' demographics, comorbidities, medications, adjunctive procedures during thrombectomy, and secondary interventions. The primary outcome measures, postintervention primary patency and postintervention secondary patency, were analyzed using Kaplan-Meier curves and Cox regression models for risk adjustment. RESULTS: During the study period, 209 open thrombectomy procedures were performed in 139 patients; 73 (35%) were undertaken in AV fistulas and 136 (65%) in grafts. Patients with upper arm fistulas (n = 52; 54% brachiocephalic, 46% brachiobasilic) and forearm fistulas (n = 16) were more likely to be male but less likely to have cerebrovascular disease or ischemic heart disease and to be receiving anticoagulation therapy compared with graft patients. After thrombectomy, the majority of patients underwent dialysis successfully (70% upper arm fistulas, 56% forearm fistulas, 63% grafts; P > .05), and 1-year survival rates were similar in all three cohorts. Postintervention primary patency at 1 year was significantly higher for AV fistulas vs grafts (33% for upper arm fistulas and 25% for forearm fistulas vs 9% for grafts; P < .05), which was confirmed in multivariate analysis, where upper arm AV fistulas had a 46% lower risk of recurrent thrombosis or secondary intervention (hazard ratio, 0.56; 95% confidence interval, 0.35-0.85; P < .05). Postintervention secondary patency at 1 year was similar between AV fistulas and grafts (44% for upper arm fistulas vs 43% for forearm fistulas vs 31% for grafts; P = .16), but in multivariate analysis, upper arm fistulas were significantly less likely to fail (hazard ratio, 0.63; 95% confidence interval, 0.40-1.00; P = .05). CONCLUSIONS: Our data suggest that AV fistula thrombectomy is successful in up to 70% of cases, with significantly improved risk-adjusted 1-year primary and secondary patency rates for upper arm fistulas compared with grafts. Whereas the risk of access failure is high after thrombectomy, efforts to salvage upper arm AV fistulas are effective in most patients and should be undertaken when feasible.